Decoupled Range and Orientation Sensing in Long-Range Magnetoquasistatic Positioning

A technique using magnetoquasistatic fields has been shown to enable accurate ranging in non-line-of-sight environments. Due to the nonlinear field coupling equations, the technique suffers when extended to 2-D and 3-D due to the coupling of range and orientation errors combined with the nonlinear convergence of the solution. Using a 2-axis transmit-receive concept, a theory is presented to decouple range and orientation. The results are linear orientation-invariant ranging and linear range-invariant orientation sensing. Measurements inverted using the decoupled equations demonstrate peak orientation-invariant range errors of 0.2-0.4 m for a range of up to over 40 m, and peak range-invariant orientation errors of 1°-7°.